JP3101403B2 - Gel moldings, their preparation and applications - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fibrous gel molded product and a method for producing the same. More specifically, the present invention relates to a net formed from a fibrous gel, such as an aquaculture net or a stationary net, or a molded product such as a water purification sludge, and a method for producing the same. Further, the present invention relates to a wastewater treatment method using a tubular material filled with a fibrous gel.

[0002]

2. Description of the Related Art Fish and shellfish are produced by aquaculture in order to secure marine resources. The target for aquaculture is pearl oysters such as pearl oysters, oysters, flatfish, kochi, hamachi, and flounder. In most of the aquaculture forms, floating fish cages using a fish net are used. However, there is a problem in that the aquaculture water area is contaminated by food for culture and excrement from fish and shellfish. As a method of purifying a culture water area, a method of applying a synthetic polymer solution to an ordinary culture net together with enzymes and microorganisms and forming a film (Japanese Patent Application Laid-Open No. 52-145592) is known. The film applied later easily falls off due to immersion or bending in water, so that there is a problem that the purification action of the water area is lost and the water area is rather contaminated by the dropped synthetic polymer.

[0003] On the other hand, in recent years, studies have been made to immobilize biocatalysts such as enzymes and microorganisms and to utilize their functions efficiently. One of the methods for immobilizing the biocatalyst is a comprehensive immobilization method in which the biocatalyst is directly wrapped using a polymer material as a carrier, and the polymer material often used in this method includes agar, alginate, carrageenan, Examples include polyacrylamide, polyvinyl alcohol, polyethylene glycol, and photocurable resins. Examples of the shape of the carrier include a sphere, a die, a sheet, and a fiber. Conventionally, there have been known research examples in which a granular carrier such as a sphere or a dice is injected into a reaction system and the efficiency of the carrier is increased. Equipment is required. However, a device such as a filter has a problem in that the device is clogged with foreign matter mixed in the wastewater.

[0004] In addition, there is also a problem that dirt is deposited in the piping through which drainage passes and the piping is blocked. In addition, a method of filling a spherical, dice-like, sheet-like or the like carrier enclosing and fixing microorganisms for purifying water in a pipe is conceivable, but also in these methods, the carrier may flow out of the system.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a net such as an aquaculture net or a stationary net in which a polymer gel does not fall off and contaminate a water area, and a filling material to be inserted into a pipe through which contaminated water passes. To provide a cleaning drip-like substance placed in a stream of polluted water or contaminated water, which exhibits a good purification function over a long period of time.

[0006]

According to the present invention, there is provided a gel comprising a core-in-sheath fibrous gel (C) in which the sheath is a water-soluble synthetic polymer (A) and the core is a fiber. The present invention provides a molded gel having a specific shape that is characterized. Typical forms of this molded product are nets such as aquaculture nets, fixed nets and the like, and a water purification sludge.

The above-mentioned gel molding can be produced by the following method. That is, a mixed aqueous solution containing a water-soluble synthetic polymer (A) and a water-soluble polysaccharide (B) capable of gelling by contact with a cation is discharged from a nozzle together with the fiber, and the discharged product is mixed with an aqueous solution containing a cation. The core-sheath fibrous gel (C) is formed by gelling the water-soluble synthetic polymer (A) to form a core-sheath fibrous gel (C), and then processed into a desired shape. It is a method characterized by shaping.

[0008] In the core-sheath fibrous gel constituting the molded article of the present invention, the fiber of the core part plays a role of forming a structure, and the gel of the water-soluble synthetic polymer (A) in the sheath part. Plays a role such as immobilization of a biocatalyst. Therefore, when the amount of the gel composed of the water-soluble synthetic polymer (A) to be coated is too small, the effect of purifying the water area deteriorates. In order to effectively fix the biocatalyst, the thickness of the sheath made of the gel of the water-soluble synthetic polymer (A) is preferably 10 μm or more, more preferably 50 μm or more.

The fibers used in the present invention include:
There is no particular limitation as long as it has a strength that can be used in a reaction tank. For example, natural fibers such as cotton, hemp, wool, silk,
Regenerated fiber such as rayon, semi-synthetic fiber such as acetate, polyamide, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, polyester, polyacrylonitrile, polyethylene, polypropylene, polyurethane, polyalkylene paraoxybenzoate And synthetic fibers of phenol, polyfluoroethylene, and the like, and inorganic fibers such as glass fiber and carbon fiber. Among these, synthetic fibers that do not undergo decomposition by a biocatalyst are preferable in view of durability in water, and synthetic fibers having a specific gravity of 1 or less are more preferable.

Examples of the water-soluble synthetic polymer (A) constituting the sheath gel of the core-sheath fibrous gel include polyvinyl alcohol (hereinafter abbreviated as "PVA"), polyacrylamide, polyethylene glycol and the like. . A gel of the water-soluble synthetic polymer (A) in which the biocatalyst is not entrapped and immobilized is also included in the scope of the present invention. It is preferable that the biocatalyst is comprehensively fixed to the surface. The biocatalyst used here is not particularly limited, and any microorganisms and enzymes can be immobilized. In addition, a gel containing the water-soluble synthetic polymer (A) of the present invention may be supplemented with a microorganism medium, a filler for adjusting the specific gravity of the produced gel, and the like, as long as the gelation is not inhibited.

Next, a method for producing the core-sheath fibrous gel will be described. First, a mixed aqueous solution containing a water-soluble synthetic polymer (A) as a main component of a gel and a water-soluble polysaccharide (B) capable of gelling by contact with a cation is prepared.
When adding a biocatalyst such as a microorganism or an enzyme, a medium for the microorganism, or a filler for adjusting the specific gravity, the mixture is added to the mixed aqueous solution. Here, specific examples of the water-soluble polysaccharide (B) capable of gelling upon contact with a cation include alginate, carrageenan, mannan, chitosan and the like, with sodium alginate being particularly preferred.

Next, an aqueous solution comprising the component (A) and the component (B) is discharged from a nozzle together with the fiber, and is brought into contact with an aqueous solution containing a cation to form a core-sheath fibrous gel. Specific examples of the cation-containing compound used herein include metal cations such as calcium ion, magnesium ion, strontium ion, barium ion, aluminum ion, potassium ion, cerium ion, and nickel ion; and cations such as ammonium ion. A compound containing at least one kind is mentioned, and calcium chloride is particularly preferable. Finally, the water-soluble synthetic polymer (A), which is the main component of the gel, is gelled to obtain a core-sheath fibrous gel.

As a method of gelling the water-soluble synthetic polymer (A), a method of contacting with a polymerization initiator / crosslinking agent to carry out polymerization / crosslinking, a method of irradiating light or an electron beam to crosslink,
A method of generating microcrystals by performing freeze-thawing at least once, a method of contacting with a compound aqueous solution having a synergic effect of the water-soluble synthetic polymer (A), and gelling may be considered.
In particular, when the biocatalyst is immobilized, a method of gelling by a method that does not inhibit its activity is preferable. In particular, a method in which freezing and thawing is performed once or more, and a method in which a polymer is brought into contact with an aqueous solution of a compound having a syneresis effect are preferable. Further, a plurality of these methods may be used in combination. When freezing and thawing are performed one or more times, the freezing temperature is preferably −5 ° C. or lower in order to generate sufficient fine crystals. Furthermore, the freeze-thaw operation may be repeated to increase the strength of the gel.

When the aqueous solution of the water-soluble synthetic polymer (A) is brought into contact with an aqueous solution of a compound having a synergic effect, the aqueous solution of the compound having a synergic effect includes sodium sulfate, ammonium sulfate, potassium sulfate, magnesium sulfate, and aluminum sulfate. And an aqueous solution containing at least one compound such as sodium citrate, ammonium citrate, potassium citrate, magnesium citrate, aluminum citrate, sodium tartrate, ammonium tartrate, potassium tartrate, magnesium tartrate, and aluminum tartrate. However, a sulfate aqueous solution is particularly preferable.

To form the core-sheath fibrous gel into a molded product such as a net or a sludge, known processing and shaping methods can be employed. For example, a net can be formed by a well-known braiding method into a frog net, a net net, a knotless net, a rope net, a Russell net, or the like. In addition, in order to form a slender material, a core-sheath fibrous gel is knotted on a rod or a string using the strength of a core yarn. Alternatively, the end of the core-sheath fibrous gel may be fixed so that it can be crimped with a knob.

The rope nodules or other shapes formed in the manner described above are used for purifying water by being introduced into the drainage flow as it is or in the form of a wound column. In addition, when purifying water by filling a fibrous gel into a tubular material, the fibrous gel can be used as it is or in any processing form.

The present invention further provides a method for treating wastewater, characterized by flowing wastewater in one direction into a tubular material filled with a fibrous gel comprising a water-soluble polymer (A) enclosing and fixing a biocatalyst. I will provide a.

The fibrous gel used for filling the pipes for purifying the wastewater preferably has the above-mentioned core-sheath composite structure in view of its strength. It may be a fibrous gel consisting of only the water-soluble synthetic polymer (A). This fibrous gel is produced according to the above-described method for producing a core-sheath fibrous gel. There is no particular limitation on the tubular material to be filled with the fibrous gel as long as it is a tubular material such as a conventional water supply pipe or sewage pipe. The filling rate of the fibrous gel in the tube is preferably from 10 to 91% by weight. If the filling ratio is too small, the water purification effect is poor, and if it is too large, the resistance to the water flow increases. A more preferable filling rate is from 20 to 75.
% By weight.

[0019]

The molded product such as a mesh or a sludge formed from the core-sheath fibrous gel used in the present invention has excellent form stability and strength because it has a core of synthetic fibers and other fibers.
The gel of the water-soluble synthetic polymer constituting the sheath does not fall off, is not affected by water, various chemical solutions, and biocatalysts, and has excellent durability. In addition, when the fibrous gel is filled in a pipe and used for purifying water, good purification performance is exhibited over a long period of time.

[0020]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 (Preparation and evaluation of aquaculture net) PVA manufactured by Kuraray Co., Ltd. (average degree of polymerization: 4000, saponification degree: 99.85 mol%) was washed with warm water at 40 ° C. for about 1 hour, and then the PVA concentration was 10% by weight. Water was added to PVA to adjust the pH to 6. This is placed in an autoclave for 12
The mixture was treated at 0 ° C. for 30 minutes to dissolve PVA, and then allowed to cool to room temperature. 25 parts by weight of a 4% aqueous sodium alginate solution was added to 50 parts by weight of this PVA aqueous solution, mixed, and further collected from seawater off Ushimado, Okayama Prefecture, and concentrated to obtain 25 parts by weight of sludge (MLSS 40000 mg / l). In addition, the mixture was sufficiently stirred.

This mixed solution was discharged together with a polyester filament (250 denier) from a nozzle having a 1.5 mm inner diameter injection needle-shaped discharge port at the tip. The discharge port is 0.2 mol / liter calcium chloride (CaC
l ₂ ) The product was immersed in an aqueous solution, and the discharged material was taken out at a speed of 5 m / min. The residence time of the discharged material in the CaCl ₂ aqueous solution was 1 minute. The ejected material immediately solidified by covering the surface of the yarn upon contact with the CaCl ₂ aqueous solution. This was lightly washed with distilled water, frozen in a freezer at −20 ° C. for 24 hours, and then thawed at room temperature. Further, the operation of freezing and thawing was repeated twice. As a result, an opaque brown flexible core-sheath fibrous gel was obtained. Using the obtained core-sheath fibrous gel, make a knotless network of mesh size 15mm × 15mm,
A cubic culture net having a length of 5 m, a width of 5 m and a height of 5 m was made.
This was immersed off Ushimado in Okayama Prefecture, where 2,000 flounders were cultured. One week later, seawater near the aquaculture net was sampled, and the TOC (total organic carbon) and ammonia nitrogen concentrations were measured.
ppm and the water quality was good. Neither the flounder died nor the fish were hurt.

Comparative Example 1 (Preparation and evaluation of aquaculture nets) Aquaculture nets of the same size as in Example 1 were produced using only the same polyester filaments as used in Example 1. This was immersed in Ushido off the coast of Okayama Prefecture, where there was flounder 200
No fish were cultivated. One week later, seawater near the aquaculture net was sampled, and the TOC (contained carbon) and ammonia nitrogen concentrations were measured. The results were 67 ppm and 5.3 ppm, respectively, and the water quality was extremely poor. Injured and dead fish were also found.

Comparative Example 2 (Preparation and evaluation of aquaculture nets) A mixed solution of PVA, sodium alginate and sludge was prepared in the same manner as in Example 1, and the same aquaculture net as in Comparative Example 1 was immersed in this mixed solution. It was immersed in a 0.2 mol / l calcium chloride (CaCl ₂ ) aqueous solution for 1 minute. The mixture adhering to the culture net immediately solidified upon contact with the CaCl ₂ aqueous solution. This was lightly washed with water, frozen in a freezer at −20 ° C. for 24 hours, and then thawed at room temperature. This freezing and thawing operation was repeated twice. This allows
A cultivation net with an opaque brown flexible gel was obtained. This culture net was immersed off Ushimado, Okayama Prefecture, and 2000 flounders were cultured. One week later, observation of the culture net revealed that most of the gel-like material had fallen off, indicating a problem in durability. The seawater near the aquaculture net was sampled, and the TOC (total organic carbon) and ammonia nitrogen concentrations were measured. The results were 52 ppm and 4.4 p, respectively.
pm, and the water purification was insufficient. Injured and dead fish were also found.

Example 2 (Preparation of Sud-like Material and Evaluation of Water Purification Function) A mixed solution of PVA, sodium alginate and sludge was prepared in the same manner as in Example 1. However, activated sludge (MLSS 80000 mg / ml) obtained as a sludge from the aeration tank of a wastewater treatment plant at the Kuraray Okayama Plant (1-2-1, Kaigandori, Okayama City, Okayama Prefecture) was subjected to a concentration action. liter)
Was used. The obtained mixed liquid was discharged together with a spun polyester yarn (20th count) from a nozzle having an injection needle-shaped discharge port having an inner diameter of 1 mm at the tip. The discharge condition is Example 1.
Same as. The discharged material was treated in the same manner as in Example 1 to obtain an opaque brown flexible core-sheath fibrous gel. This core-sheath fibrous gel is tied to a longline (thin rope-shaped string) made of polyester spun yarn at intervals of 5 mm, and the width of the core is 20 mm.
cm, 14 cm long, and fixed to a metal frame. This drip-like material was suspended in a polyvinyl chloride tank having a width of 20 cm, a depth of 15 cm, and a length of 10 m so that the tank volume was 5% (volume percentage). From one end of this tank,
Untreated effluent from Kuraray Okayama Plant is treated as TOC (total organic carbon)
The wastewater obtained by adjusting to 50 ppm was injected at 2.5 L / min. At this time, the water flowing out from the other end of the tank was collected, and the TOC was measured.
The water was found to be purified.

Comparative Example 3 (Preparation of Sud-like Material and Evaluation of Water Purification Function) Polyester spun yarn (20th count) was tied to a longline (thin rope-shaped string) made of polyester spun yarn at intervals of 5 mm, and the width was 20 cm. It was formed into a 14-cm-long slender shape, and a plurality of pieces were fixed to a metal frame. This is 20cm wide and 15c deep
m, 5% of the tank volume in a 10m long polyvinyl chloride tank
(Volume percentage). From one end of this tank, the waste water obtained by adjusting the waste water untreated water TOC (total organic carbon) of the Kuraray Okayama Plant to 50 ppm was 2.5 ppm.
Injected at liter / min. At this time, the water flowing out from the other end of the tank was collected and the TOC was measured.
pm and the water was not purified.

Example 3 (Formation of Filling and Evaluation of Water Purification Function) An opaque brown flexible core-sheath fibrous gel was prepared in the same manner as in Example 2. This fibrous gel has an inner diameter of 13 mm and an outer diameter of 18 m.
The inside of the tube made of polyvinyl chloride having a length of 10 m and a length of 10 m was filled with 50% by volume. From one end of this tube, a drainage liquid obtained by adjusting the waste water untreated water TOC (total organic carbon) of the Kuraray Okayama Plant to 50 ppm was injected at 500 ml / min.
At this time, the water flowing from the other end of the pipe is collected, and the TOC is collected.
Was 10 ppm, and it was found that water was purified by passing water through the inside of the tube.

Comparative Example 4 (Preparation of Filling Material and Evaluation of Water Purification Function) Five spun polyester yarns (20th count) were placed inside a polyvinyl chloride pipe having an inner diameter of 13 mm, an outer diameter of 18 mm, and a length of 10 m.
0% by volume was filled. From one end of this tube, a wastewater obtained by adjusting untreated wastewater from Kuraray Okayama Plant to a TOC of 50 ppm was injected at 500 ml / min. At this time, water flowing out from the other end of the tube was collected, and the TOC was measured. The result was 49 ppm, and the water was not purified.

[0028]

As is evident from the above examples, the mesh of the present invention using the core-sheath fibrous gel fulfills the function of a conventional mesh and can simultaneously purify water areas, so that it can be used for rivers, lakes and marshes. High practical value in sea areas. Also, the fish body is not damaged. In addition, the sludge-like material of the present invention has excellent durability without the gel-like material falling off over a long period of time, without being affected by water, various chemical solutions, and biocatalysts.
Therefore, this drool retains a good purification function for a long period of time. Further, when contaminated water is passed through a tubular article filled with a fibrous gel, good purification is achieved, so that a purification function can be imparted to a water supply pipe, a sewage pipe, or the like.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ identification code FI D06M 15/03 D06M 15/03 (58) Investigated field (Int.Cl. ⁷ , DB name) D06M 15/00-15/715 D01F 8/00-8/18

Claims (4)

(57) [Claims] 1. A molded product of a reticulated gel, wherein the sheath portion is a gel made of a water-soluble synthetic polymer (A) and the core portion is made of a core-sheath fibrous gel (C) which is a fiber. . 2. A slender gel molding, wherein the sheath is a gel made of a water-soluble synthetic polymer (A) and the core is made of a core-sheath fibrous gel (C) which is a fiber. Stuff. 3. A mixed aqueous solution containing a water-soluble synthetic polymer (A) and a water-soluble polysaccharide (B) capable of gelling by contact with a cation is discharged from a nozzle together with the fiber, and the discharged material is converted into a cation. The core-sheath fibrous gel (C) is formed by contacting with an aqueous solution containing the solution, and further, the water-soluble synthetic polymer (A) is gelled to form a core-sheath fibrous gel (C). 3. The method for producing a gel molded product according to claim 1, wherein the gel is formed into a desired shape. 4. A method for treating wastewater, comprising: flowing wastewater in one direction into a tubular material filled with a fibrous gel comprising a water-soluble polymer (A) enclosing and fixing a biocatalyst.